The Study Of Molecular Mechanism With RegⅢγ In The Mucosal Immunity Effect Mediated By Multiple Forms Lactobacillus

The intestinal epithelial barrier is the biggest barrier of the body.Produced by the islets of pancreas(ating),RegⅢγ plays an important role in intestinal innate immunity. In this study we found that IL-23/IL-22 factor and MyD88(differentiation factor88 myeloid, MyD88) can promote the expression of RegⅢγ. RegⅢγ can decrease inflammation and promote tissue healing. Which plays an important role in resisting and reducing the pathogenesis and development of the inflammatory bowel disease(Inflammatory Bowel, Disease, IBD). Lactobacillus as the dominant bacteria in the intestine, can stimulate intestinal epithelial cells and advance the maturity of dendritic cells, through interacting with the intestinal epithelial cells, to enhance the intestinal immune defense function and maintain the health of the body. But it is not clear how the Lactobacillus cause intestinal epithelial cells to produce RegⅢγ, and the effect and mechanism of Lactobacillus on IBD inflammatory process is not known. In this research, we analyzed the effects of Lactobacillus on the expression of RegⅢ in vivo and on the changes of inflammatory factors in ulcerative colitis, to explore the production mechanism, the molecular mechanism and immune defense function of RegⅢγ in mucosal immunity of enteritis. The results are as follows:(1) Effects of difference doses of multiple Lactobacillus on expression of RegⅢγ in intestines of normal mousebased on preliminary test, the study selected mixed Lactobacillus with probiotic function,to vaccinate healthy mice in high and low doses, and the activation of dendritic cells, MyD88, IL-23, IL-22 cytokine and RegⅢγ expression changes in intestinals tract of mice were observed by fluorescence quantitative PCR, flow cytometry, enzyme linked immunosorbent assay(ELISA) and immune group technology, to explore the molecular mechanism of different doses of Lactobacillus induced secretion of RegⅢγ in healthy mice, and screen out the optimal dose of Lactobacillus. The results showed that the mixed Lactobacillus propagated in healthy mice intestinal tract caused the higher expression level of RegⅢγ, and there was significant difference compared with the control group(P<0.05). the mixed Lactobacillus significantly increased the activation number of dendritic cells in vivo, and this result was different from that of the control group(P<0.01). Consistent with the trend of activated dendritic cells, the expression of IL-23, IL-22 and MyD88 in the gut of mice was significantly increased, and the disparity was significant(P<0.01). The test also indicated that the high dose of Lactobacillus had immune on intestinal tracts.(2) Effects of RegⅢγ induced by mixed Lactobacillus on mucosal immunity of bacterial colitisIBD is a chronic, inflammatory intestinal disease, with complex causes and difficulty of treatment. The Lactobacillus as probiotics have been shown to enhance the body’s intestinal immune ability. As an important immune factor in intestinal innate immunity, the antimicrobial protein RegⅢγ is attracting people,s attention gradually. Based on previous work, we screened out high-dosage mixed Lactobacillus with the good probiotic activity to mediating the mice and checked intestinal RegⅢγ, MPO and serum SAA expression by IFA, hematoxylin eosin(he) staining and ELISA. At the same time, we monitored intestinal pathological changes and mucosal immune function of ulcerative colitis mices which were inoculated with mixed Lactobacillus. The results showed that the expression of RegⅢγ was significantly increased in the model of enteritis(P<0.005), but the amount of RegⅢγ in the Lactobacillus group was significantly lower than DSS group(P<0.01). The detection results of the Lactobacillus group were significantly lower than those of the DSS group in the intestinal pathological examination, intestinal inflammatory factor MPO and systemic inflammatory response SAA(P<0.01),(P<0.05). In summary, Lactobacillus can improve the body’s resistance to the enteritis caused by DSS, which may be related to RegⅢγ.In conclusion, the high-dose of mixed Lactobacillus can activate dendritic cells, and up-regulate the expression of IL-23, IL-22 and MyD88 to increase RegⅢγ secretion. In this process, the Lactobacillus group showed the more efficient role in mediation. The further research showed that in the process of enteritis by DSS, high-dose of mixed Lactobacillus mediated RegⅢγ immune response to inhibit inflammatory factors and reduce inflammatory reaction.